Medical device with control circuitry to improve communication quality

ABSTRACT

A method for managing power during communication with an implantable medical device, including establishing a communications link, utilizing a power corresponding to a session start power, to initiate a current session between an implantable medical device (IMD) and external device. A telemetry break condition of the communications link is monitored during the current session. The power utilized by the IMD is adjusted between low and high power levels, during the current session based on the telemetry break condition. The number of sessions is counted, including the current session and one or more prior sessions, in which the IMD utilized the higher power level, and a level for the session start power to be utilized to initiate a next session following the current session is adaptively learned based on the counting of the number of sessions.

REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of, and claimspriority to U.S. application Ser. No. 16/994,951, Titled “MEDICAL DEVICEWITH CONTROL CIRCUITRY TO IMPROVE COMMUNICATION QUALITY” which was filedon 17 Aug. 2020 which is a continuation application of, and claimspriority to, U.S. application Ser. No. 16/743,109, Titled “MEDICALDEVICE WITH CONTROL CIRCUITRY TO IMPROVE COMMUNICATION QUALITY” whichwas filed on 15 Jan. 2020 (now U.S. Pat. No. 10,785,720, issued 22 Sep.2020) which is a continuation application of, and claims priority to,U.S. application Ser. No. 16/255,178, Titled “MEDICAL DEVICE WITHCONTROL CIRCUITRY TO IMPROVE COMMUNICATION QUALITY” which was filed on23 Jan. 2019 (now abandoned), the complete subject matter of which areexpressly incorporated herein by reference in their entirety.

BACKGROUND

Embodiments of the present disclosure generally relate to medicaldevices with control circuitry to improve communication quality whileminimizing battery consumption.

An implantable medical device (IMD) is a medical device that isconfigured to be implanted within a patient anatomy and commonly employsone or more electrodes that either receive or deliver voltage, currentor other electromagnetic pulses from or to an organ or tissue fordiagnostic or therapeutic purposes. In general, IMDs include a battery,electronic circuitry, a pulse generator, a transceiver and/or amicroprocessor that is configured to handle communication with anexternal instrument as well as control patient therapy. The IMD iscompletely enclosed within the human body. Thus, there is no means ofdirect interaction with an IMD, other than through wirelesscommunication.

However, IMDs are typically built with non-replaceable batteries thatlimit options for communications solutions. Typically, the wirelesscommunication is maintained utilizing a low range, low powercommunications platform during short periods of time. Existingcommunication solutions experience certain limitations regarding powerconsumption. For example, in some environments, current consumption or,more generally, energy usage during communication remains a concern inthe IMD. For a Bluetooth Low Energy (BLE) enabled IMD, currentconsumption by the IMD during advertising is particularly of interest asenergy usage during advertising can significantly impact the IMD batterylongevity.

A need remains for improved methods and devices for establishingminimizing battery consumption and energy while still providing aquality communication link to external instruments.

BRIEF SUMMARY

A method for managing power during communication with an implantablemedical device, including establishing a communications link, utilizinga power corresponding to a session start power, to initiate a currentsession between an implantable medical device (IMD) and external device.A telemetry break condition of the communications link is monitoredduring the current session. The power utilized by the IMD is adjustedbetween low and high power levels, during the current session based onthe telemetry break condition. The number of sessions is counted,including the current session and one or more prior sessions, in whichthe IMD utilized the higher power level, and a level for the sessionstart power to be utilized to initiate a next session following thecurrent session is adaptively learned based on the counting of thenumber of sessions.

Optionally, the monitoring the telemetry break condition includescounting at least one of a number of return errors or a number of badpackets received by the IMD. Alternatively, adjusting the powercomprises changing from the low power level to the high power levelduring the current session in response to the telemetry break conditionindicating an actual or potential telemetry break. In one example, thetelemetry break condition indicates the potential telemetry break isbased on a measured signal to noise ratio during the session.

In one aspect, the method also includes determining an in-session powertransition occurs from the low power level to the high power level, andin response thereto, incrementing the count of the number of sessions inwhich the IMD utilized the high power level. In another aspect themethod includes determining if the count of the number of sessions inwhich the IMD utilized the high power level has reached a thresholdvalue; and in response to reaching the threshold value, decreasing thepower utilized by the IMD during the next session.

Optionally, the monitoring the telemetry break condition includesdetermining no return errors or bad packets were received by the IMDduring the session. In another aspect, responsive to determining noreturn errors or bad packets are received by the IMD during the session,the method includes decrementing the count of the of the number ofsessions in which the IMD is utilizing the high power level.Specifically, adjusting the power comprises changing from the high powerlevel to the low power level for the next session in response tostarting a pre-determine amount of sessions at the high power level.

In another aspect, establishing a communications link, utilizing a powercorresponding to a session start power, to initiate a current sessionbetween an implantable medical device (IMD) and external device includesbroadcasting an advertisement message during an interval andtransitioning into a sleep mode when a connection is not establishedduring the interval.

In another example, a system for managing power during communicationwith an implantable medical device, is provided that includes one ormore processors configured to execute instructions to establish acommunications link, utilizing a power corresponding to a session startpower, to initiate a current session between an implantable medicaldevice (IMD) and external device, and monitor a telemetry breakcondition of the communications link during the current session. The oneor more processors also adjust the power utilized by the IMD, betweenlow and high power levels, during the current session based on thetelemetry break condition, count a number of sessions, including thecurrent session and one or more prior sessions, in which the IMDutilized the higher power level, and adaptively learn a level for thesession start power to be utilized to initiate a next session followingthe current session based on the counting of the number of sessions.

Optionally, the one or more processors are further configured to executeinstructions to monitor the telemetry break condition by counting atleast one of a number of return errors or a number of bad packetsreceived by the IMD. In another aspect, the one or more processors arefurther configured to execute instructions to adjust the power bychanging from the low power level to the high power level during thecurrent session in response to the telemetry break condition indicatingan actual or potential telemetry break. Optionally, the telemetry breakcondition indicates the potential telemetry break is based on a measuredsignal to noise ratio during the session. In an example, the one or moreprocessors are further configured to execute instructions to determinean in-session power transition occurs from the low power level to thehigh power level, and in response thereto, increment the count of thenumber of sessions in which the IMD utilized the high power level. Inanother aspect, the one or more processors are further configured toexecute instructions to: determine if the count of the number ofsessions in which the IMD utilized the high power level has reached athreshold value; and in response to reaching the threshold value,decrease the power utilized by the IMD during the next session.

In one aspect, the one or more processors are further configured toexecute instructions to monitor the telemetry break condition bydetermining no return errors or bad packets were received by the IMDduring the session. Optionally, the one or more processors are furtherconfigured to execute instructions to: responsive to determining noreturn errors or bad packets are received by the IMD during the session,decrement the count of the of the number of sessions in which the IMD isutilized the high power level. Additionally, the one or more processorsare configured to execute instructions to adjust the power compriseschanging from the high power level to the low power level for the nextsession in response to starting a pre-determine amount of sessions atthe high power level.

In another example, the one or more processors are further configured toexecute instructions to establish a communications link, utilize a powercorresponding to a session start power, to initiate a current sessionbetween an implantable medical device (IMD) and external device bybroadcasting an advertisement message during an interval andtransitioning into a sleep mode when a connection is not establishedduring the interval.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a simplified block diagram of a communication systemoperated in accordance with embodiments herein.

FIG. 2 illustrates a block diagram of communication circuitry operatedin accordance with embodiments herein.

FIG. 3 illustrates a block diagram of an external instrument operated inaccordance with embodiments herein.

FIG. 4 illustrates a block flow chart of a method in accordance withembodiments herein.

FIG. 5 illustrates a simplified block diagram of a communication systemoperated in accordance with embodiments herein.

FIG. 6 illustrates a block flow chart of a method in accordance withembodiments herein.

FIG. 7 illustrates a graph of power usage over time in accordance withembodiments herein.

FIG. 8 illustrates a graph of power usage over time in accordance withembodiments herein.

DETAILED DESCRIPTION

It will be readily understood that the components of the embodiments asgenerally described and illustrated in the figures herein, may bearranged and designed in a wide variety of different configurations inaddition to the described example embodiments. Thus, the following moredetailed description of the example embodiments, as represented in thefigures, is not intended to limit the scope of the embodiments, asclaimed, but is merely representative of example embodiments.

Reference throughout this specification to “one embodiment” or “anembodiment” (or the like) means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, appearances of the phrases “in oneembodiment” or “in an embodiment” or the like in various placesthroughout this specification are not necessarily all referring to thesame embodiment.

Provided is a power management system and scheme for wirelesscommunications, such as BLE communications, that decreases batteryconsumption while optimizing radio frequency (RF) performance. Undercurrent power management schemes, the signal power level is set to avalue high enough to achieve minimum required communication range. Inone example, the signal power level is set to less than the maximumpower possible from the wireless communication device, that in anexample is a BLE chip. Once this signal power is set, it never changesthroughout the lifetime of the device. As a result, when operating inenvironments with significant RF interference, the device experiencescommunication difficulties such as actual telemetry breaks, potentialtelemetry breaks, telemetry break conditions, dropped communicationsignals, static, poor sound quality, and the like.

While increasing the signal power may improve chances of connecting toan external instrument, or device, this also results in wasted energywhen such increased signal power is unneeded. Specifically, when BLEcommunications are not being used, which is most of the time, the IMDcannot decrease the signal power during an advertising mode or datatransfer to save battery life. This inefficient use of battery leads toother consequences such as the need for longer advertisement periods(1-4 minutes, which leads to long delay before a successful connection)in order to meet longevity requirements or have a direct impact onlongevity.

Therefore, the communication system provided recognizes thecommunication environment surrounding the IMD. As an example, the IMDrecognizes when the communication system is being used, and during thosetimes, such as during an in clinic visit, during a scheduled remote carefollow-up, or during a patient initiated follow up, can increase thesignal power level if the environment is noisy to improve the wirelessconnection and communication. Meanwhile, when communication is notactive, and/or the environment is not noisy, the signal returns to alower, or low, power level to decrease battery consumption and improvelongevity.

The term “actual telemetry break”, as used herein, refers to a conditionin which a communications link has at least temporarily ended due to oneor more of return errors and/or bad packets received by an IMD.

The term “potential telemetry break”, as used herein, refers to acondition in which a communications link is maintained, but experiencesa number of return errors and/or bad packets received by an IMD inexcess of a threshold, thereby indicating a high likelihood that thecommunications link is about to end.

The term “telemetry break condition”, as used herein, refers to acondition of a communications link with respect to an actual orpotential telemetry break.

The terms “low power” and “high power”, as used herein, do not refer toabsolute power levels, but instead referred to power levels relative toone another.

FIG. 1 illustrates a simplified block diagram of a system 100 operatedin accordance with embodiments herein. The system 100 includes one ormore IMD 101 and one or more external instrument (EI) 201 (e.g., tablecomputer, smart phone, smart watch, laptop, and/or the like) that areconfigured to communicate with one another wirelessly over acommunications link 140.

The IMD 101 is implanted within a patient 106 (e.g., proximate to and/orwithin a heart 103, proximate to the spinal cord). Non-limiting examplesof IMDs include one or more of neurostimulator devices, implantableleadless monitoring and/or therapy devices, and/or alternativeimplantable medical devices. For example, the IMD may represent acardiac monitoring device, pacemaker, cardioverter, cardiac rhythmmanagement device, defibrillator, neurostimulator, leadless monitoringdevice, leadless pacemaker and the like. For example, the IMD mayinclude one or more structural and/or functional aspects of thedevice(s) described in U.S. Pat. No. 9,333,351 “Neurostimulation MethodAnd System To Treat Apnea” and U.S. Pat. No. 9,044,610 “System AndMethods For Providing A Distributed Virtual Stimulation Cathode For UseWith An Implantable Neurostimulation System”, which are herebyincorporated by reference. Additionally or alternatively, the IMD mayinclude one or more structural and/or functional aspects of thedevice(s) described in U.S. Pat. No. 9,216,285 “Leadless ImplantableMedical Device Having Removable And Fixed Components” and U.S. Pat. No.8,831,747 “Leadless Neurostimulation Device And Method Including TheSame”, which are hereby incorporated by reference. Additionally oralternatively, the IMD may include one or more structural and/orfunctional aspects of the device(s) described in U.S. Pat. No. 8,391,980“Method And System For Identifying A Potential Lead Failure In AnImplantable Medical Device” and U.S. Pat. No. 9,232,485 “System AndMethod For Selectively Communicating With An Implantable MedicalDevice”, which are hereby incorporated by reference. Additionally oralternatively, the IMD 101 may be a leadless monitor, examples of whichare disclosed in U.S. patent application Ser. No. 15/084,373, filed Mar.29, 2016, entitled, “METHOD AND SYSTEM TO DISCRIMINATE RHYTHM PATTERNSIN CARDIAC ACTIVITY,” which is expressly incorporated herein byreference.

FIG. 2 illustrates a block diagram of a communication circuitry 200 ofan IMD that in one example is the IMD 101 of FIG. 1. The componentsdescribed herein can include or represent hardware and softwareinstructions (e.g., software stored on a tangible and non-transitorycomputer readable storage medium, such as a computer hard drive, ROM,RAM, or the like) that perform the operations described herein. Thehardware may include electronic circuits that include and/or areconnected to one or more logic-based devices, such as microprocessors,processors, controllers, or the like. Additionally or alternatively, thecomponents may be hard-wired logic circuits.

The communication circuitry 200 is within the housing 210 of an IMD. Thehousing 210 is often referred to as the “can”, “case” or “caseelectrode” and may be programmably selected to act as the returnelectrode for all “unipolar” modes. The housing 210 may further be usedas a return electrode alone or in combination with one or more of thecoil electrodes for shocking purposes. The housing 210 further includesa connector (not shown) having a plurality of terminals. The terminalsmay be configured to be coupled to different types of electrodes andleads. In one example embodiment the IMD is a pacemaker.

The communication circuitry 200 is configured to manage thecommunication link between the IMD 101 and external devices. In oneexample the communication circuitry 200 may be configured to handleand/or manage the bi-directional communication link 140 between the IMD101 and the EI 201. In one example the communication circuitry 200 is anRF circuit.

In another example the communication circuitry 200 includes atransponder that transmits signals and a receiver that receives signals.In yet another example, the communication circuitry 200 includes atransceiver 212 (TX/RX) that both transmits signals and receivessignals. Specifically, a transceiver includes both a transponder and areceiver. As explained herein, the communication circuitry 200transmits, among other things, advertising notices in accordance withone or more advertising schedules. The transceiver 212 is tuned tocommunicate with external devices, including the EI 201 over one or morefrequency bands and in accordance with a corresponding protocol. Thetransceiver 212 may include one or more transmitters/transponders,receivers, and/or transceivers. Optionally, the communication circuitry200 may be electrically coupled to an antenna (not shown). For example,an antenna may be provided within a header of an IMD as one example. Asanother example, electrodes on or coupled to the IMD may be utilized toconvey the wireless communication signals. The communication circuitry200 also scans for connection request data packets from externaldevices. In one example the external device is the EI 201 of FIG. 1.

The communication circuitry 200 also includes one or more processors 214including a communication control processor 215, a local memory 216, andtelemetry circuitry 218, all of which may be implemented on a commoncircuit board, within a common subsystem or within a common integratedcircuit. Specifically, the communication circuitry 200 is incommunication with other circuits, components, and modules of the IMD101 including controller circuit, and IMD local memory 216. Thecommunication control processor 215 may support one or more wirelesscommunication protocols while communicating with an external device suchas the EI 201, such as Bluetooth low energy, Bluetooth, Medical ImplantCommunication Service (MICS), and/or the like.

The memory 216 stores instructions implemented by the communicationcontrol processor 215. Protocol firmware may be stored in memory 216,which is accessed by the communication control processor 215. Theprotocol firmware provides the wireless protocol syntax for thecommunication control processor 215 to assemble data packets,advertisement notices, connection request data packets, connectionresponses, establish communication links, such as communication 140,and/or partition data received from an external device, such as EI 201.

The telemetry circuitry 218 in one example monitors the quality of thetelemetry or communications link 140. Alternatively, the telemetrysoftware is stored in the memory that provides instructions that arefollowed by the communication control processor or one or more of theprocessors 214 related to the communication circuitry 200. The telemetrycircuitry 218 in one example determines when the link, and/or how oftenthe link 140 drops causing interruptions in communications being passedthrough the communications link 140. In another example the telemetrycircuitry 218 determines the number of return errors received, number ofbad packets received, or the like. Optionally, the telemetry circuitry218 tracks the signal to noise ratio (RSSI) of the communication link140. When the communication link 140 is down or not working thetelemetry circuitry 218 verifies the power setting of the telemetry linkand increases the power setting when a break in the link 140 occurs, orwhen a link 140 is unable to be established. In this manner, thetelemetry circuitry 218 facilitates re-establishment of the link 140 toassist in completing communication sessions. Thus, the telemetrycircuitry 218 not only makes determinations regarding when communicationbreaks occur including timing to reestablish the link 140 and the like,but additionally, the quality of the telemetry link is determinedthrough various methods including RSSI. The telemetry circuitry 218 alsoactively corrects any breaks or poor quality communications byincreasing power to establish and maintain the link 140.

FIG. 3 illustrates a distributed processing system 300 in accordancewith one embodiment. In one example, the distributed processing system300 includes and implements processes of the communication circuitry 200as provided in FIG. 2. The distributed processing system 300 includes aserver 302 connected to a database 304, a programmer 306, a local RFtransceiver 308 and a user workstation 310 electrically connected to acommunication system 312. Any of the processor-based components in FIG.3 (e.g., workstation 310, cell phone 314, PDA 316, server 302,programmer 306, IMD 101) may communicate with an IMD 317 that in oneexample is IMD 101 of FIG. 1. In one example, the local RF transceiver308 is the transceiver of 212 of FIG. 2, and the communication system312 includes communication circuitry 200 of FIG. 2.

The communication system 312 may be the internet, a voice over IP (VoIP)gateway, a local plain old telephone service (POTS) such as a publicswitched telephone network (PSTN), a cellular phone based network, andthe like. Alternatively, the communication system 312 may be a localarea network (LAN), a campus area network (CAN), a metropolitan areanetwork (MAN), or a wide area network (WAN). The communication system312 serves to provide a network that facilitates the transfer/receipt ofinformation such as cardiac signal waveforms, ventricular and atrialheart rates.

The server 302 is a computer system that provides services to othercomputing systems over a computer network. The server 302 controls thecommunication of information such as cardiac signal waveforms,ventricular and atrial heart rates, and detection thresholds. The server302 interfaces with the communication system 312 to transfer informationbetween the programmer 306, the local RF transceiver 308, the userworkstation 310 as well as a cell phone 314, a personal data assistant(PDA) 316, and IMD 317 to the database 304 for storage/retrieval ofrecords of information. On the other hand, the server 302 may upload rawcardiac signals from an implanted lead 322, surface ECG unit 320 or theIMD 317 via the local RF transceiver 308 or the programmer 306.

The database 304 stores information such as cardiac signal waveforms,ventricular and atrial heart rates, thresholds, and the like, for asingle or multiple patients. The information is downloaded into thedatabase 304 via the server 302 or, alternatively, the information isuploaded to the server from the database 304. The programmer 306 issimilar to an external device or instrument and may reside in apatient's home, a hospital, or a physician's office. The programmer 306interfaces with the lead 322 and the IMD 317. The programmer 306 maywirelessly communicate with the IMD 317 and utilize protocols, such asBluetooth, GSM, infrared wireless LANs, HIPERLAN, 3G, satellite, as wellas circuit and packet data protocols, and the like. Alternatively, ahard-wired connection may be used to connect the programmer 306 to theIMD 317. The programmer 306 is able to acquire cardiac signals from thesurface of a person (e.g., ECGs), intra-cardiac electrogram (e.g., IEGM)signals from the IMD 317, and/or cardiac signal waveforms, ventricularand atrial heart rates, and detection thresholds from the IMD 317. Theprogrammer 306 interfaces with the communication system 312, either viathe internet or via POTS, to upload the information acquired from thesurface ECG unit 320, the lead 322 or the IMD 317 to the server 302.

The local RF transceiver 308 interfaces with the communication system312 to transmit and receive telemetry data and information beingtransmitted to and from the RF transceiver 308. In one example thecommunication system monitors the communication link and recordstelemetry breaks, length of breaks, number of breaks in a giveninterval, time to reestablish a signal, signal to noise ratio, and thelike. In this manner the communication system 312 provides with a userthe quality and/or strength of a communication signal and amount orstrength of local interference. In addition, the communication system312 may, based on the monitored communication quality, increase ordecrease the power of a signal being transmitted. In one example, thecommunication system 312 monitors both advertising channels andconnection channels, thus providing advertising data packets through andcommunicating through the advertising channels with external devicessuch as external instruments. Similarly, the communication system 312 isable to provide a communication pathway through a connection channel.

The user workstation 310 may interface with the communication system 312to download cardiac signal waveforms, ventricular and atrial heartrates, and detection thresholds via the server 302 from the database304. Alternatively, the user workstation 310 may download raw data fromthe surface ECG units 320, lead 322 or IMD 317 via either the programmer306 or the local RF transceiver 308 or cell phone 314 or PDA 316. Oncethe user workstation 310 has downloaded the cardiac signal waveforms,ventricular and atrial heart rates, or detection thresholds, the userworkstation 310 may process the information in accordance with one ormore of the operations described above. The user workstation 310 maydownload the information and notifications to the cell phone 314, thePDA 316, the local RF transceiver 308, the programmer 306, or to theserver 302 to be stored on the database 304. For example, the userworkstation 310 may communicate data to the cell phone 314, PDA 316, orIMD 317 via a wireless communication link 326. In one example, thewireless communication link 326 is the communication link 140 of FIG. 1.

Process for Managing Power During Communication

FIG. 4 thus illustrates a flow block diagram of a method 400 formanaging power during communication with an implantable medical device(IMD). In one example the IMD is the IMD 101 of FIGS. 1-2. In anotherexample, the IMD includes communication circuitry 200 as provided inFIG. 2. The method 400 may be implemented by hardware components,software components, and/or a combination of hardware components andsoftware components working together to implement the method.

At 402, one or more processors establish a communications link,utilizing a power corresponding to a session start power, to initiate acurrent session between an IMD and external device. In one example, thecommunications link is the communications link 140 of FIG. 1. In anotherexample, the communication link utilizes protocols, such as Bluetooth,GSM, infrared wireless LANs, HIPERLAN, 3G, satellite, as well as circuitand packet data protocols, and the like. Alternatively, a hard-wiredconnection may be used to provide the communications link. In oneexample, the one or more processors establish the communications link bybroadcasting an advertisement message during an interval. Optionally,when a response is not received during the interval to the advertisingmessage, the one or more processors transitions the IMD into a sleepmode, thus saving power.

At 404, one or more processors monitor for a telemetry break conditionof the communications link during the current session. In one example,the telemetry break condition is an actual break where communication islost for a predetermined interval and must be restored or reestablished.The predetermined interval may be a second, less than a second, morethan a minute, and the like. In another example, the telemetry breakcondition is a potential telemetry break. The potential telemetry breakis determined based on measured parameters such as signal strength,interference noise level, signal to noise ratio, and the like. In oneexample a threshold is provided related to one of these parameters, sucha signal to noise ratio, that once exceeded, or once falling below thethreshold indicates the potential telemetry break is presented. In oneexample monitoring the telemetry break condition includes determining anumber of return errors from sent data packets. In another example,monitoring includes determining the number of bad packets received bythe IMD.

At 406, one or more processors adjust the power utilized by the IMDbetween low and high power levels, during the current session based onthe telemetry break condition. In one example the power is adjusted whena pre-existing condition occurs, such as to increase the power from lowpower to high power during a current session in response to a telemetrybreak. Alternatively, the power increases from a low power to a highpower during a current session when the signal to noise ratio dropsbelow a threshold level during a current session.

At 408, one or more processors counts a number of sessions, includingthe current session and one or more prior sessions, in which the IMDutilized the higher power level or lower power. In one example, when theone or more processors determine an in-session power transition occursfrom the low power level to the high power level, and in responsethereto, the one or more processors increment the count of the number ofsessions in which the IMD utilized the high power level. The incrementcan be represented by a numerical value, such as one, another numericalvalue, or the like. The one or more processors optionally can determineif the count of the number of sessions in which the IMD utilized thehigh power level has reached a threshold value; and in response toreaching the threshold value, increase the power utilized by the IMDduring the next session. In another example, the count increases basedon an algorithm or weighted determination. In one example, when thepower level is increased because of one preexisting condition such as atelemetry break, a first count amount or score is added to the count,such as two points, whereas when a second preexisting condition such asa signal to noise ratio falling below a threshold amount, a differentamount or score is added to the count such as one. Thus, differentmeasured events may result in the same result to the count, such asadding one to a count, or may result in a different result to the count.Similarly, in one example, when the count is increased duringconsecutive sessions, more weight can be provided to the subsequentconsecutive increase. Thus, if power is switched from low to high duringa first session, the count increases by 1, but if the power is switchedfrom the low to high power three (3) sessions in a row, the count willincrease by 2 as a result of the third consecutive increased session.

At 410, the one or more processors adaptively learn a level for thesession start power to be utilized to initiate a next session followingthe current session based on the counting of the number of sessions. Inone example, the one or more processors keep track of the count at 408and when the count reaches a threshold level, then when a next sessionbegins the one or more processors automatically provide a high powerlevel to start the next session. In one example, the count is 10. Inanother example the count can increase and decrease. Specifically, in anexample when a non-telemetry break condition includes determining noreturn errors or bad packets were received by the IMD during thesession, the count may be decremented. In yet another example, multipleiterations of counts can occur. Specifically, a first count may providethe amount of times a telemetry break occurs during sessions while asecond count may provide the amount of times a signal to noise ratio isbelow a threshold, while yet another count determines the amount of timeeither a telemetry break or a signal to noise ratio is below thethreshold. By keeping track of the count of predetermined events thatindicate the interference level in a known environment, the one or moreprocessors are able to adaptively determine the start power for a givenenvironment while keeping power usage low for other environments anduses. Thus, the power usage does not need to remain elevated at timesthe elevated power level is unneeded. Consequently, power is saved,increasing battery life.

FIGS. 5 and 6 illustrate two common use cases for a power scheme thatare user initiated in clinic communication and scheduled remote caremonitoring/user initiated remote care transmission. First, for the userinitiated in clinic communication use case illustrated in the block flowdiagram of FIG. 5, the user initiates the communication with analternative method such as inductive telemetry. The one or moreprocessors of the IMD set the power-flag of the implant to use maximumpower for communication, because the timing demand and uncertainty ofoperational environment in the in-clinic. In this case, the implantsubsequently uses the maximum transmit power to advertise, connect toexternal devices, and transfer data packets for the connection session.When the session is finished, the one or more processors of the IMD setsthe power-flag to a remote care power setting.

Therefore, FIG. 5 illustrates a method 500 for managing power duringcommunication with an IMD. In one example the IMD is the IMD 101 ofFIGS. 1-2. In another example, the IMD includes communication circuitry200 as provided in FIG. 2. The method 500 may be implemented by hardwarecomponents, software components, and/or a combination of hardwarecomponents and software components working together to implement themethod.

At 502, one or more processors based on inductive telemetry command acommunication connection. In one example the communication connection isa BLE connection. In one example, a patient with an IMD has a scheduledin-person appointment within an environment, that in this example is aclinic.

At 504, a power-flag is set to use maximum power for communication. Inone example, the maximum power is a predetermined level. When usedherein a “flag” is utilized as understood in a computer science contextand is considered a bit or bit sequence that is used by a program, orone or more processors, to remember or leave a sign for another programfor use. In this manner, when the one or more processors operate todetermine the power level that should be utilized during a visit orappointment in a pre-determined environment, the processors immediatelydetermine maximum power shall be utilized in the environment. In anexample, a program that is not the program that makes the maximum powerdetermination sets the flag and is separate, or a different program thanthe program that utilizes the flag, or maximum power command in order tobegin learning the clinic environment. In other words, for this commonuse case, when an IMD is to be within a new communications environment,such as a first time within the communications environment of apre-determined clinic, method 500 provides examples of how thecommunication circuitry sets its power level to a maximum power settingwithin such a new environment for the initial visit to provide as muchpower as possible during an initial communication session.Alternatively, as illustrated and described in relation to FIG. 6, apower flag is not set to have an initial maximum power setting, and thusthe system starts at a minimum or low power setting.

At 506, the IMD communicates with an external instrument (EI) using thecommunication connection. In one example, the communication connectionis a BLE connection. In an example, the EI is a monitor that providesmedical data related to the IMD and patient based on a communicationsession through the communication connection. In particular, at thistime a patient is within the clinic environment during an appointmentand testing is occurring by a clinician. Because the maximum power isbeing utilized, an optimal communication environment is formed by theIMD to provide optimal medical data from the communication session.

At 508 a decision is made regarding whether the session is done. If not,the communication session continues, and the IMD remains at a maximumpower level to continue to provide an optimal communication link forgathering the desired medical data. At 508, in one example the decisionmade regarding whether a session is done is made in two differentmanners. In a first determination, a signal, prompt, or the like isprovided that the session is complete, ending the session at 510. Insuch an example the signal, prompt, or the like may be provided by theEI, a remote clinician device such as a computer, tablet, or the like, aremote patient device such as a handheld phone, watch, or the like.Alternatively, at 512, a telemetry break occurs that exceeds apre-determined time period, or limit. In one example the pre-determinedtime period is one hour. Specifically, if the EI and IMD do not exchangeinformation, or communicate with one another for an hour, the one ormore processors determine the communication session is complete. If thecommunication session is not complete, the communication session may berestarted through inductive telemetry utilizing methods as previouslydescribed.

If at 508, a determination is made that the communication session isdone, either through a command 510 or through a session timing out 512,at 514, the power flag is set to a minimum power setting. In one examplethe minimum power setting is considered a remote care power setting.Again, a bit or bit sequence provides the remote care power setting forthe one or more processors of the IMD to utilize in subsequent uses orenvironments. In this manner, when a maximum power is desired forcommunication in the clinic environment, a maximum power state isprovided, while when not in a clinic environment, a minimum amount ofpower is provided. Consequently, power consumption is more efficient,power is saved, extending battery life.

The second common use case is for remote care monitoring as illustratedin FIG. 6. In this use case, the one or more processors of the IMD setsa power-flag to use a remote care power setting after it comes out fromshipped setting. In other words, instead of the power setting beingaltered before entering a clinic environment to provide an initialmaximum power setting as described in relation to FIG. 5, the power-flaginstead remains at a minimum power setting when entering the clinicianenvironment and must self-correct, or adjust to the clinic environmentbased on active and on-going telemetry quality monitoring. Specifically,the transmit power level is set to low power, the max power sessioncount is set to 0, and the max power session flag is set to false. Afterthe remote care communication session begins, the IMD monitors thequality of the telemetry link. If one telemetry break or number oftelemetry breaks occurs, the IMD checks if the max power setting hasbeen used. If yes, it will keep using the max power setting and try tore-establish the link and finish the session. If not, the IMD switchesto max power setting and attempts to re-establish the link and finishthe session.

If the telemetry doesn't break, the one or more processors also checkthe quality of the telemetry link through various additional methods,including relative received signal strength (RSSI). In one example theRSSI is determined as provided in methodologies related to IEEE 802.11.Alternatively, return errors and bad data packets are counted. If thequality is deemed too low, the processors of the IMD also set the powerlevel to max. After the session is finished, the one or more processorsof the IMD check if the session starts and exits with max power setting.If the session starts as a low power session, but ends in a high powersession, a new high power session is provided. The max power sessioncounter therefore increases by 1. When the max power session counterreaches a threshold, the max power session indicates the communicationenvironment is not ideal. The device thus sets the remote carecommunication power to max power for the next session to increase thesuccessful rate.

In the next session, the remote care session starts with high power, andthe IMD increases the max power setting count by 1. If the max sessioncount exceeds a predefined threshold, such as N, the IMD switches thepower setting to low power to try low power for the next remote caresession. In the next session starting with low power, if thecommunication is successful, the device will decrease the max powersetting count by 1, until 0. If the communication is not successful anddevice switches to max power, the device will increase the max powersetting count by 1 and the subsequent remote care session will startwith high power again.

Thus, as illustrated in relation to FIG. 6, a method 600 of managingpower during communication with an IMD is provided. In one example theIMD is the IMD 101 of FIGS. 1-2. In another example, the IMD includescommunication circuitry 200 as provided in FIG. 2. The method 600 may beimplemented by hardware components, software components, and/or acombination of hardware components and software components workingtogether to implement the method.

At 602, the IMD enters a remote care communication session. In oneexample the communication session is entered in a clinic environmentwherein the patient has an appointment for a clinician to monitor theoperation of the IMD and health of the patient. The communicationsession is entered into as a result of the appointment or monitoring. Inanother example, the remote care communication session is entered intoas a result of in home monitoring of a patient.

At 604, the one or more processors begin the communication session at apredetermined power setting. In one example the pre-determined powersetting is set at a maximum power level as described in relation to FIG.5. Alternatively, the power setting is set at a minimum power as aresult of a first or initial use of the IMD in the clinic environment.Alternatively, the power setting is set as determined by the one or moreprocessors utilizing the methodology as provided in this method 600 aswill be described in full herein.

At 606 a determination is made whether there is a telemetry breakcondition is provided. In one example the telemetry break conditionoccurs when a signal is lost resulting in a telemetry break.Alternatively, the potential telemetry break condition is determinedbased on measured parameters such as signal strength, interference noiselevel, signal to noise ratio, and the like. In one example a thresholdis provided related to one of these parameters, such a signal to noiseratio, that once exceeded, or once falling below the threshold indicatesthe potential telemetry break is presented. In one example monitoringthe telemetry break condition includes determining a number of returnerrors from sent data packets.

Thus, at 608 if a telemetry break occurs at 606 flow goes to the rightand the one or more processors determine if the maximum power flag isset as true. In one example the maximum power flag is set as true as aresult of the initial power setting being set at a maximum power asprovided in the method of FIG. 5. Alternatively, the maximum power flagis set as true as a result of determination made in this method 600 ofFIG. 6.

If at 608 the maximum power flag is set at a maximum power, then theflow goes to the right and the one or more processors determine whetherthe session has ended at 610. Alternatively, if the maximum power flagis not set at maximum power, then the flow goes down and at 612 thepower level is increased. In one example the power level is increase toa maximum power level, thus going from a low power level to a high powerlevel. In another example the power level is increased incrementally toa level higher than the initial power level, but not to a maximum powerlevel. Regardless, after the power level is increased, the determinationis made regarding whether the session has ended at 610.

If at 606 a telemetry break has not occurred, then at 614 the one ormore processors determine whether a signal to noise ratio is above apredetermined threshold. In one example, the determination is madeutilizing RSSI. If the determination is made that the signal to noiseratio has not reached the predetermined threshold, thus indicating apotential for a telemetry break and thus that a telemetry breakcondition is provide, then flow goes to the right to 608 to determine ifthe maximum power flag is set to at a maximum power. Thus, flow moves asdescribed above. Alternatively, a number of signal errors, and/or baddata packets are counted to make a similar determination related to thetelemetry break condition.

If at 614 the signal to noise ratio is above a predetermined threshold,or other telemetry break condition do not exist, then flow movesdownward to 610 for a determination regarding whether the session hasended. Specifically, in this example if a telemetry break condition isnot detected and the signal to noise ratio is above a predeterminethreshold, a telemetry break condition is not presented. In otherexamples, additional determinations may be made regarding whether atelemetry break condition is presented and considered during suchdeterminations. Factors related to the telemetry break condition mayinclude the number of return errors, number of bad packets, or the likeduring a communication session.

If at 610 the session has not ended, then the communication sessioncontinues at 616 and the one or more processors continue to attempt todetermine if a telemetry break condition is occurring at 606.Importantly, the one or more processors continue to attempt to establisha strong communication path and in examples when the power has beenincrementally increased at 612, the increased power level may result inthe telemetry break condition from not occurring, resulting in adifferent outcome and the one or more processors thus learns the powerlevel needed for the given clinical environment.

Once the communication session has ended at 610, flow moves downward to618 and a determination is made whether a maximum power session flag wasoriginally set to true. In one example, the flag of the communicationsession is set as true as described in FIG. 5. Alternatively andadditionally, the maximum power flag is set at true as a result of thismethod 600 described herein.

If at 618, the maximum power session flag was set to true, flow moves tothe left and the one or more processors increase a max power sessioncount by a predetermined amount at 619. In one example the count isincreased by one.

At 620, after the power increases by the predetermined amount, adetermination is made regarding whether the count meets or exceeds apredetermined threshold value. In one example the predetermined count issixteen (16). If the predetermined count does not meet or exceed thethreshold value, then flow moves to the left and the method continues at622 with the initial power setting at a maximum power level.

Alternatively, if at 620 the count meets or exceeds a predeterminedthreshold value, at 624 the maximum power session flag is set to falseand at 626 the remote care power is set to low power. In this example,once a maximum power session flag is determined for 604, the IMDautomatically starts at the maximum power level for a predeterminedamount of times, in this example sixteen. After the threshold amount ofsessions is complete, the one or more processors changes the maximumpower session flag to false, thereby resulting in the initial powersetting of the next session to be low and the maximum power sessioncount is reset. Therefore, the process forces a retry of thecommunication environment to make determinations if changes in thecommunication environment have occurred that result in maximum power usebeing unneeded. If maximum power is still required, the method worksthrough to increase the power setting to a maximum setting as describedherein to ensure the proper power level is provided. Specifically, thecount remains the same, such that if power is increased during thesubsequent session, the initial maximum power requirement isreinitiated. If the communication environment has changed and maximumpower is no longer required, then the system operates with low power inthe communication environment, saving power usage and battery life.Thus, after the remote care power is returned to low power at 626 themethod continues at 622.

If at 618 the communication session was initiated, and the maximum powersession was not set as true, then at 628, the one or more processorsdetermine if an in-session power transition occurs from a low powerlevel to the high power level. In one example, this increase is a localincrease, or in other words, the maximum power level of the IMD is notreached, however an incremental increase in power has occurred duringthe session. For example, if at 612 power is increased, a local maximumpower of the IMD is determined as a “Yes”, or is determined to bepresented, even though the IMD is not at a maximum power for the IMD.Specifically, the one or more processors are attempting to determinewhen power has to be increased or maximized during a session as a resultof a telemetry break condition.

If at 628 the power level was not increased from a low level to a high,or higher level during the session, then flow moves left from 628 andthe max power session count is decreased by one (−1) at 629.Specifically, if the power level does not start at a maximum power leveland does need to be increased during a session, then a goodcommunication environment is determined and the count to increase thepower level initially during a subsequent session is decreasedaccordingly to prevent an unnecessary increase in power. Then the methodcontinues at 622.

Alternatively, if at 628 the power level did increase from a low powerlevel to a high or higher power level during a session, the incrementalmaximum power session count is increased by a predetermined amount at630. In one example the predetermined amount is one (1). In yet anotherexample the count is increased by more than one based on pre-existingconditions. For example, if the power level is increased from an initialpower to a higher power for three consecutive sessions, the count in thethird consecutive session may increase by two instead of only one.Alternatively, more weight may be provided to increasing to a maximumpower level, or otherwise, to increase the count.

After the maximum power count is increased at 630, at 632 adetermination is made whether the maximum power session count meets orexceeds a threshold count. In one example the threshold count to 10. Ifthe threshold is not met or exceeded, then the flow moves downward, andthe method continues with no change in the initial power setting for asubsequent, or next communication session and the methodology continuesat 622. If at 632 the threshold count is met or exceeded, then flowmoves left, and the maximum power session flag is changed to true at 634and the remote care power flag is changed to maximum at 636. Therefore,in one example, if the power in a clinic environment must be increasedfrom low power to high power in ten separate sessions, a poorcommunication environment is determined, and the initial power settingis maximized for the next communication session to ensure clearcommunication and data exchange between the IMD and EI. Thus, at thispoint the methodology continues at 622.

In an example experiment an IMD was set up as a peripheral thatbroadcasted an advertisement message (Tx) then listened for a responsesignal (Rx) on each of three advertisement channels occurring atpredetermined intervals. During the predetermined intervals the IMD goesinto a sleep mode if no connection is established. Such an advertisingscheme is illustrated in the graph of FIG. 7. As shown in FIG. 7, duringthe advertising period, the process may utilize a higher power level totransmit an advertisement notice and utilize a lower power level tolisten for a response signal. Specifically, the time during advertisingis the advertising period while the time the IMD is in sleep mode is asleep period, while the time between a first advertisement and a secondadvertisement is an advertising interval.

The calculation of average current over a 5 second advertising interval(Iavg@5s Adv interval) is as follows:

${{{Iavg}@5}s\mspace{14mu}{Adv}\mspace{14mu}{internal}} = \frac{\left( {{{Iadv} \times {Tadv}} + {{Islp} \times \left( {{5\mspace{14mu} s} - {Tadv}} \right)}} \right)}{5\mspace{14mu} s}$

Where lady is the advertising current in milli amps (mA), Tadv is theadvertisement period in milli seconds (ms), and Islp is the sleepcurrent in nano Amps (nA).

After the IMD is connected to an EI, the IMD continues to transmit emptypackets at every connection interval to maintain the communication linkas illustrated in the graph of FIG. 8. The data packet may include apayload of up to 255 bytes and is transmitted across the link by the IMDat each connection interval when data is available. Specifically, theIMD comes out of standby or sleep mode to transmit the packet, and thengoes to back into standby or sleep mode to wait for a next connectioninterval. The connection and data transfer process is thusly illustratedin FIG. 8. As shown in FIG. 8, during a connection interval, the processmay utilize a higher power level to transmit data packets during atransmit operation and utilize a lower power level to listen during areceive operation.

Table 1 illustrates a first table with the average current ofadvertising with a five second advertising interval at 0 dBm (decibelsin relation to one milli Watt), 3 dBm, and 6 dBm. Specifically, 3 dBmoutput power increases a link budget by 3 dB, or extends thecommunication range by 43%, and by using 6 dBm can increase a linkbudget by 6 dBm or extend the communication range by 102% and are thusutilized accordingly.

TABLE 1 Power Level Average Current (mA) Current Saving 0 dBm 1.37 56.9%3 dBm 1.81 55.5% 6 dBm 3.94   0%

Table 2 meanwhile provides a table of the average current and savings oftransferring an 80-byte payload packet for various power levels,similarly at 0 dBm, 3 dBm, and 6 dBm.

TABLE 2 Power Level Average Current (mA) Current Saving 0 dBm 3.6 68.1%3 dBm 5.5 50.3% 6 dBm 11.3   0%

Table 3 meanwhile illustrates the average current and savings oftransferring an empty packet for power levels at 0 dBm, 3 dBm, and 6dBm.

TABLE 3 Power Level Average Current (mA) Current Saving 0 dBm 2.4 48.9%3 dBm 3.3 29.8% 6 dBm 4.7   0%

The average current of a user scenario of continuously streaming twoEGMs (electrograms) is provided in Table 4 below. Specifically, with anassumption of 10 ms connection interval and sending one 80 byte datapacket every four connection intervals to achieve a data rate of 2 KB/s,the calculation is provided in Table 4 using the following calculation:

${Iavg} = \frac{\begin{matrix}{{{I{data}} \times {T{data}}} + {N \times {I{empty}} \times {T{empy}}} + {{I{standby}} \times}} \\\left( {{\left( {N + 1} \right) \times {T{interval}}} - {T{data}} - {N \times {T{empty}}}} \right)\end{matrix}}{\left( {N + 1} \right) \times {T{interval}}}$

Where Iavg is the average current in uA, Idata is the data packetcurrent in mA, Tdata is the data packet period in ms, N is the number ofempty packets between data packets in counts, Iempty is the Empty packetcurrent in mA, Tempty is the empty packet period in ms, Istanby is thestandby current in uA, and Tinteval is the connection interval in ms.Thus, Table 4 below illustrates the average current and savingsstreaming two channels of EGM for power levels of 0 dBm, 3 dBm, and 6dBm.

TABLE 4 Power level Average Current (mA) Current Saving 0 dBm 1.02 55.5%3 dBm 1.18 48.0% 6 dBm 2.29   0%

Thus, by utilizing the methodologies herein numerous advantages overother systems and methods are achieved. By utilizing maximum powerduring communication sessions, a better user experience resultsincluding having a more robust communication link, more immunity toambient interferences, and experience fewer interruptions to the link.By utilizing power switching, the system and methodology allows thedevice to switch to lower power when the link quality is good or when acommunication session is not active. Consequently, power consumption isdecreased, resulting in increased IMD life.

Additionally, the method and system may be retrofit into currentapplications because it is communication IC (integrated chip)independent, or BLE IC independent. Thus, the method and system may beimplemented on all such devices including existing devices.Consequently, better connectivity and patient experience is achieved.

CLOSING STATEMENT

It should be clearly understood that the various arrangements andprocesses broadly described and illustrated with respect to the Figures,and/or one or more individual components or elements of sucharrangements and/or one or more process operations associated of suchprocesses, can be employed independently from or together with one ormore other components, elements and/or process operations described andillustrated herein. Accordingly, while various arrangements andprocesses are broadly contemplated, described and illustrated herein, itshould be understood that they are provided merely in illustrative andnon-restrictive fashion, and furthermore can be regarded as but mereexamples of possible working environments in which one or morearrangements or processes may function or operate.

As will be appreciated by one skilled in the art, various aspects may beembodied as a system, method or computer (device) program product.Accordingly, aspects may take the form of an entirely hardwareembodiment or an embodiment including hardware and software that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects may take the form of a computer (device) programproduct embodied in one or more computer (device) readable storagemedium(s) having computer (device) readable program code embodiedthereon.

Any combination of one or more non-signal computer (device) readablemedium(s) may be utilized. The non-signal medium may be a storagemedium. A storage medium may be, for example, an electronic, magnetic,optical, electromagnetic, infrared, or semiconductor system, apparatus,or device, or any suitable combination of the foregoing. More specificexamples of a storage medium would include the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), a dynamicrandom access memory (DRAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), a portablecompact disc read-only memory (CD-ROM), an optical storage device, amagnetic storage device, or any suitable combination of the foregoing.

Program code for carrying out operations may be written in anycombination of one or more programming languages. The program code mayexecute entirely on a single device, partly on a single device, as astand-alone software package, partly on single device and partly onanother device, or entirely on the other device. In some cases, thedevices may be connected through any type of network, including a localarea network (LAN) or a wide area network (WAN), or the connection maybe made through other devices (for example, through the Internet usingan Internet Service Provider) or through a hard wire connection, such asover a USB connection. For example, a server having a first processor, anetwork interface, and a storage device for storing code may store theprogram code for carrying out the operations and provide this codethrough its network interface via a network to a second device having asecond processor for execution of the code on the second device.

Aspects are described herein with reference to the figures, whichillustrate example methods, devices and program products according tovarious example embodiments. These program instructions may be providedto a processor of a general purpose computer, special purpose computer,or other programmable data processing device or information handlingdevice to produce a machine, such that the instructions, which executevia a processor of the device implement the functions/acts specified.The program instructions may also be stored in a device readable mediumthat can direct a device to function in a particular manner, such thatthe instructions stored in the device readable medium produce an articleof manufacture including instructions which implement the function/actspecified. The program instructions may also be loaded onto a device tocause a series of operational steps to be performed on the device toproduce a device implemented process such that the instructions whichexecute on the device provide processes for implementing thefunctions/acts specified.

The units/modules/applications herein may include any processor-based ormicroprocessor-based system including systems using microcontrollers,reduced instruction set computers (RISC), application specificintegrated circuits (ASICs), field-programmable gate arrays (FPGAs),logic circuits, and any other circuit or processor capable of executingthe functions described herein. Additionally or alternatively, themodules/controllers herein may represent circuit modules that may beimplemented as hardware with associated instructions (for example,software stored on a tangible and non-transitory computer readablestorage medium, such as a computer hard drive, ROM, RAM, or the like)that perform the operations described herein. The above examples areexemplary only, and are thus not intended to limit in any way thedefinition and/or meaning of the term “controller.” Theunits/modules/applications herein may execute a set of instructions thatare stored in one or more storage elements, in order to process data.The storage elements may also store data or other information as desiredor needed. The storage element may be in the form of an informationsource or a physical memory element within the modules/controllersherein. The set of instructions may include various commands thatinstruct the modules/applications herein to perform specific operationssuch as the methods and processes of the various embodiments of thesubject matter described herein. The set of instructions may be in theform of a software program. The software may be in various forms such assystem software or application software. Further, the software may be inthe form of a collection of separate programs or modules, a programmodule within a larger program or a portion of a program module. Thesoftware also may include modular programming in the form ofobject-oriented programming. The processing of input data by theprocessing machine may be in response to user commands, or in responseto results of previous processing, or in response to a request made byanother processing machine.

It is to be understood that the subject matter described herein is notlimited in its application to the details of construction and thearrangement of components set forth in the description herein orillustrated in the drawings hereof. The subject matter described hereinis capable of other embodiments and of being practiced or of beingcarried out in various ways. Also, it is to be understood that thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings herein withoutdeparting from its scope. While the dimensions, types of materials andcoatings described herein are intended to define various parameters,they are by no means limiting and are illustrative in nature. Many otherembodiments will be apparent to those of skill in the art upon reviewingthe above description. The scope of the embodiments should, therefore,be determined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled. In the appendedclaims, the terms “including” and “in which” are used as theplain-English equivalents of the respective terms “comprising” and“wherein.” Moreover, in the following claims, the terms “first,”“second,” and “third,” etc. are used merely as labels, and are notintended to impose numerical requirements on their objects or order ofexecution on their acts.

What is claimed is:
 1. A method, comprising: establishing acommunications link, utilizing a communication power level correspondingto a session start power, to initiate a current session between animplantable medical device (IMD) and external device; monitoring atleast one of a quality or a condition of the communications link duringthe current session; changing the communication power level during thecurrent session; and tracking power usage by the IMD, the power usage atleast partially indicative of a power consumption by the IMD to maintainthe communications link.
 2. The method of claim 1, wherein theestablishing the communications link includes broadcasting advertisementnotices at the session start power.
 3. The method of claim 2, furthercomprising transmitting the advertisement notices at a maximum transmitpower.
 4. The method of claim 1, wherein the communications power levelduring the current session is lower than the session start power.
 5. Themethod of claim 1, wherein the changing includes actively increasing ordecreasing the communications power level during the current session tomaintain the communications link.
 6. The method of claim 1, wherein themonitoring includes monitoring a relative received signal strength(RSSI) as an indicator of the quality of the communications link.
 7. Themethod of claim 1, wherein the establishing the communications linkfurther comprises, during an advertising period, utilizing a high powerlevel to transmit an advertisement notice and utilizing a low powerlevel to listen for a response signal.
 8. The method of claim 1, furthercomprising, during a connection interval of the communications session,utilizing a high power level during a transmit operation and utilizing alow power level during a receive operation.
 9. The method of claim 1,wherein the monitoring comprises monitoring the telemetry breakcondition.
 10. The method of claim 1, wherein the monitoring comprisesmonitoring the quality of the communications link.
 11. A system,comprising: one or more processors configured to execute instructionsto: establish a communications link, utilizing a communication powerlevel corresponding to a session start power, to initiate a currentsession between an implantable medical device (IMD) and external device;monitor at least one of a quality or a condition of the communicationslink during the current session; change the communication power levelduring the current session; and track power usage by the IMD, the powerusage at least partially indicative of a power consumption by the IMD tomaintain the communications link.
 12. The system of claim 11, wherein,to establish the communications link, the one or more processors arefurther configured to broadcast advertisement notices at the sessionstart power.
 13. The system of claim 12, wherein the one or moreprocessors are further configured to transmit the advertisement noticesat a maximum transmit power.
 14. The system of claim 11, wherein thecommunications power level during the current session is lower than thesession start power.
 15. The system of claim 11, wherein, to change thecommunications power level, the one or more processors are furtherconfigured to actively increase or decrease the communications powerlevel during the current session to maintain the communications link.16. The system of claim 11, wherein the one or more processors arefurther configured to monitor a relative received signal strength (RSSI)as an indicator of the quality of the communications link.
 17. Thesystem of claim 11, wherein, to establish the communications link, theone or more processors are further configured to, during an advertisingperiod, utilize a high power level to transmit an advertisement noticeand utilize a low power level to listen for a response signal.
 18. Thesystem of claim 11, wherein the one or more processors are furtherconfigured to, during a connection interval of the communicationssession, utilize a high power level during a transmit operation andutilize a low power level during a receive operation.
 19. The system ofclaim 11, wherein the one or more processors are further configured tomonitor the telemetry break condition.
 20. The system of claim 11,wherein the one or more processors are further configured to monitor thequality of the communications link.